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在量化交易系统中。有些事件是远端传来的,比方股票的价格数据等。所以,在这一节我们定义了一个远端事件实体。
它是一个基类。并不单独生成数据表。
详细代码例如以下:
package org.cryptocoinpartners.schema; import javax.annotation.Nullable; import javax.persistence.Basic; import javax.persistence.MappedSuperclass; import javax.persistence.Transient; import org.hibernate.annotations.Type; import org.joda.time.Instant; @MappedSuperclass public abstract class RemoteEvent extends Event { /** * @return the time when this event object was created. it may be later than getTime() due to transmission delays */ @Type(type = "org.jadira.usertype.dateandtime.joda.PersistentInstantAsMillisLong") @Basic(optional = false) public Instant getTimeReceived() { return timeReceived; } @Transient public long getTimestampReceived() { return timestampReceived; } @Basic(optional = true) public String getRemoteKey() { return remoteKey; } @Override public void publishedAt(Instant instant) { super.publishedAt(instant); if (timeReceived == null) timeReceived = instant; this.timestampReceived = timeReceived.getMillis(); } protected RemoteEvent(Instant time, @Nullable String remoteKey) { this(time, Instant.now(), remoteKey); } protected RemoteEvent(Instant time, Instant timeReceived, @Nullable String remoteKey) { super(time); this.remoteKey = remoteKey; this.timeReceived = timeReceived; this.timestampReceived = timeReceived.getMillis(); } // JPA protected RemoteEvent() { } protected void setTimeReceived(Instant timeReceived) { this.timeReceived = timeReceived; this.timestampReceived = timeReceived.getMillis(); } protected void setRemoteKey(@Nullable String remoteKey) { this.remoteKey = remoteKey; } private Instant timeReceived; private long timestampReceived; private String remoteKey; }